<!-- Creator : groff version 1.19.2 --> <!-- CreationDate: Wed Jul 14 08:43:43 2010 --> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta name="generator" content="groff -Thtml, see www.gnu.org"> <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> <meta name="Content-Style" content="text/css"> <style type="text/css"> p { margin-top: 0; margin-bottom: 0; } pre { margin-top: 0; margin-bottom: 0; } table { margin-top: 0; margin-bottom: 0; } </style> <title>SEGY2GRD</title> </head> <body bgcolor="#ffffff"> <h1 align=center>SEGY2GRD</h1> <a href="#NAME">NAME</a><br> <a href="#SYNOPSIS">SYNOPSIS</a><br> <a href="#DESCRIPTION">DESCRIPTION</a><br> <a href="#OPTIONS">OPTIONS</a><br> <a href="#EXAMPLES">EXAMPLES</a><br> <a href="#SEE ALSO">SEE ALSO</a><br> <hr> <a name="NAME"></a> <h2>NAME</h2> <p style="margin-left:11%; margin-top: 1em">segy2grd − Converting SEGY file to grid file format</p> <a name="SYNOPSIS"></a> <h2>SYNOPSIS</h2> <p style="margin-left:11%; margin-top: 1em"><b>segy2grd</b> <i>segyfile</i> <b>−G</b><i>grdfile</i> <b>−I</b><i>xinc</i>[<i>unit</i>][<b>=</b>|<b>+</b>][/<i>yinc</i>[<i>unit</i>][<b>=</b>|<b>+</b>]] <b>−R</b><i>west</i>/<i>east</i>/<i>south</i>/<i>north</i>[<b>r</b>] [ <b>−A</b>[<b>n</b>|<b>z</b>] ] [ <b>−D</b><i>xname</i>/<i>yname</i>/<i>zname</i>/<i>scale</i>/<i>offset</i>/<i>title</i>/<i>remark</i> ] [ <b>−F</b> ] [ <b>−N</b><i>nodata</i> ] [ <b>−S</b>[<i>zfile</i>] ] [ <b>−V</b> ] [ <b>−Z</b>[<i>flags</i>] ] [ <b>−:</b>[<b>i</b>|<b>o</b>] ] [ <b>−bi</b>[<b>s</b>|<b>S</b>|<b>d</b>|<b>D</b>[<i>ncol</i>]|<b>c</b>[<i>var1</i><b>/</b><i>...</i>]] ]</p> <a name="DESCRIPTION"></a> <h2>DESCRIPTION</h2> <p style="margin-left:11%; margin-top: 1em"><b>segy2grd</b> reads an IEEE SEGY file and creates a binary grid file. Either a simple mapping (equivalent to xyz2grd -Z) or a more complicated averaging where a particular grid cell includes values from more than one sample in the SEGY file can be done. <b>segy2grd</b> will report if some of the nodes are not filled in with data. Such unconstrained nodes are set to a value specified by the user [Default is NaN]. Nodes with more than one value will be set to the average value. <i><br> segyfile</i></p> <p style="margin-left:22%;">ASCII [or binary] file holding z or (x,y,z) values. xyz triplets do not have to be sorted (for binary triplets, see <b>−b</b>). 1-column z tables must be sorted and the <b>−Z</b> must be set).</p> <table width="100%" border=0 rules="none" frame="void" cellspacing="0" cellpadding="0"> <tr valign="top" align="left"> <td width="11%"></td> <td width="3%"> <p style="margin-top: 1em" valign="top"><b>−G</b></p> </td> <td width="8%"></td> <td width="78%"> <p style="margin-top: 1em" valign="top"><i>grdfile</i> is the name of the binary output grid file.</p></td> <tr valign="top" align="left"> <td width="11%"></td> <td width="3%"> <p style="margin-top: 1em" valign="top"><b>−I</b></p> </td> <td width="8%"></td> <td width="78%"> <p style="margin-top: 1em" valign="top"><i>x_inc</i> [and optionally <i>y_inc</i>] is the grid spacing. Append <b>m</b> to indicate minutes or <b>c</b> to indicate seconds.</p> </td> <tr valign="top" align="left"> <td width="11%"></td> <td width="3%"> <p style="margin-top: 1em" valign="top"><b>−R</b></p> </td> <td width="8%"></td> <td width="78%"> <p style="margin-top: 1em" valign="top"><i>west, east, south,</i> and <i>north</i> specify the Region of interest, and you may specify them in decimal degrees or in [+-]dd:mm[:ss.xxx][W|E|S|N] format. Append <b>r</b> if lower left and upper right map coordinates are given instead of w/e/s/n. The two shorthands <b>−Rg</b> and <b>−Rd</b> stand for global domain (0/360 and -180/+180 in longitude respectively, with -90/+90 in latitude). Alternatively, specify the name of an existing grid file and the <b>−R</b> settings (and grid spacing, if applicable) are copied from the grid.</p></td> </table> <a name="OPTIONS"></a> <h2>OPTIONS</h2> <table width="100%" border=0 rules="none" frame="void" cellspacing="0" cellpadding="0"> <tr valign="top" align="left"> <td width="11%"></td> <td width="3%"> <p style="margin-top: 1em" valign="top"><b>−A</b></p> </td> <td width="8%"></td> <td width="78%"> <p style="margin-top: 1em" valign="top">Add up multiple values that belong to the same node (same as <b>−Az</b>). Append <b>n</b> to simply count the number of data points that were assigned to each node. [Default (no <b>−A</b> option) will calculate mean value]. Not used for simple mapping.</p></td> <tr valign="top" align="left"> <td width="11%"></td> <td width="3%"> <p style="margin-top: 1em" valign="top"><b>−D</b></p> </td> <td width="8%"></td> <td width="78%"> <p style="margin-top: 1em" valign="top">Give values for <i>xname, yname, zname, scale, offset, title,</i> and <i>remark</i>. To leave some of these values untouched, specify = as the value.</p></td> <tr valign="top" align="left"> <td width="11%"></td> <td width="3%"> <p style="margin-top: 1em" valign="top"><b>−F</b></p> </td> <td width="8%"></td> <td width="78%"> <p style="margin-top: 1em" valign="top">Force pixel registration [Default is grid registration].</p></td> <tr valign="top" align="left"> <td width="11%"></td> <td width="3%"> <p style="margin-top: 1em" valign="top"><b>−N</b></p> </td> <td width="8%"></td> <td width="78%"> <p style="margin-top: 1em" valign="top">No data. Set nodes with no input sample to this value [Default is NaN].</p></td> <tr valign="top" align="left"> <td width="11%"></td> <td width="3%"> <p style="margin-top: 1em" valign="top"><b>−S</b></p> </td> <td width="8%"></td> <td width="78%"> <p style="margin-top: 1em" valign="top">set variable spacing <i>header</i> is c for cdp, o for offset, b<number> for 4-byte float starting at byte number If -S not set, assumes even spacing of samples at the dx, dy supplied with -I</p></td> <tr valign="top" align="left"> <td width="11%"></td> <td width="3%"> <p style="margin-top: 1em" valign="top"><b>−L</b></p> </td> <td width="8%"></td> <td width="78%"> <p style="margin-top: 1em" valign="top">Override number of samples in each trace</p></td> <tr valign="top" align="left"> <td width="11%"></td> <td width="3%"> <p style="margin-top: 1em" valign="top"><b>−X</b></p> </td> <td width="8%"></td> <td width="78%"> <p style="margin-top: 1em" valign="top">applies scalar <i>x-scale</i> to coordinates in trace header to match the coordinates specified in -R</p></td> <tr valign="top" align="left"> <td width="11%"></td> <td width="3%"> <p style="margin-top: 1em" valign="top"><b>−Y</b></p> </td> <td width="8%"></td> <td width="78%"> <p style="margin-top: 1em" valign="top">Specifies sample interval as <i>s_int</i> if incorrect in the SEGY file</p></td> <tr valign="top" align="left"> <td width="11%"></td> <td width="3%"> <p style="margin-top: 1em" valign="top"><b>−M</b></p> </td> <td width="8%"></td> <td width="78%"> <p style="margin-top: 1em" valign="top">Fix number of traces to read in. Default tries to read 10000 traces. -M0 will read number in binary header, -Mn will attempt to read only n traces.</p></td> <tr valign="top" align="left"> <td width="11%"></td> <td width="3%"> <p style="margin-top: 1em" valign="top"><b>−V</b></p> </td> <td width="8%"></td> <td width="78%"> <p style="margin-top: 1em" valign="top">Selects verbose mode, which will send progress reports to stderr [Default runs "silently"].</p></td> </table> <a name="EXAMPLES"></a> <h2>EXAMPLES</h2> <p style="margin-left:22%; margin-top: 1em">To create a grid file from an even spaced SEGY file test.segy, try</p> <p style="margin-left:22%; margin-top: 1em">segy2grd test.segy <b>−I</b>0.1/0.1 <b>−G</b>test.grd <b>−R</b>198/208/18/25 <b>−V</b></p> <p style="margin-left:22%; margin-top: 1em">Note that this will read in 18-25s (or km) on each trace, but the first trace will be assumed to be at X=198</p> <p style="margin-left:22%; margin-top: 1em">To create a grid file from the SEGY file test.segy, locating traces according to the CDP number, where there are 10 CDPs per km and the sample interval is 0.1, try</p> <p style="margin-left:22%; margin-top: 1em">segy2grd test.segy <b>−G</b>test.grd <b>−R</b>0/100/0/10 <b>−I</b>0.5/0.2 <b>−V −X</b>0.1 <b>−Y</b>0.1</p> <p style="margin-left:22%; margin-top: 1em">Because the grid interval is larger than the SEGY file sampling, the individual samples will be averaged in bins</p> <a name="SEE ALSO"></a> <h2>SEE ALSO</h2> <p style="margin-left:11%; margin-top: 1em"><i><A HREF="GMT.html">GMT</A></i>(1), <i><A HREF="grd2xyz.html">grd2xyz</A></i>(1), <i><A HREF="grdedit.html">grdedit</A></i>(1), <i><A HREF="pssegy.html">pssegy</A></i>(1)</p> <hr> </body> </html>